<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>localStorage</title>
</head>
<body>
    <h2>localStorage</h2>
    <button onclick="saveData()">点我保存一个数据</button>
    <button onclick="readData()">点我读取一个数据</button>
    <button onclick="deleteData()">点我删除一个数据</button>
    <button onclick="deleteAllData()">点我清空数据</button>

</body>

<script type="text/javascript">

    let p = {name: '张三',age: 18};

    function saveData(){
        localStorage.setItem('msg','hello!!');
        localStorage.setItem('msg2',666);
        localStorage.setItem('person',JSON.stringify(p));
    }

    function readData(){
        console.log(localStorage.getItem('msg'));
        console.log(localStorage.getItem('msg2'));

        const result = localStorage.getItem('person');
        console.log(JSON.parse(result));

        // 读取一个不存在的数据，返回null
        console.log(localStorage.getItem('msg3'));

    }
    
    function deleteData(){
        localStorage.removeItem('msg2')
    }

    function deleteAllData(){
        localStorage.clear();
    }


</script>


</html>